Difficulties in Defaunation of the Ovine Rumen

Lovelock, L.K.A.; Forsbkrg, C.W.; Buchanan-Smith, J. G.

doi:10.4141/cjas82-032

Cited by 20 publications

(5 citation statements)

References 3 publications

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“…Repeated defaunation resulted in a similar length of the period when no protozoa were observed. Thus, the obtained results showed that the method mentioned above was only partially successful, and are in good accordance with the results of Lovelock et al (1982).…”

Section: Resultssupporting

confidence: 77%

“…Starvation of the second adult sheep for 24 h before treatment with the same detergent affected the length of the ciliate-free period but small Entodinia were found as soon as on the 7th day after treatment and this was followed by the spontaneous re-establishment of other species. Our findings contradict the results of other authors who were able to eliminate the protozoa from the rumen by the use of dioctyl sodium sulphoscuccinate (Orpin, 1977;Lovelock et al, 1982;Nogia and Rita, 1994). The differences in feeding regimes could explain this discrepancy.…”

Section: Resultscontrasting

confidence: 57%

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The importance of washing the omasum for successful defaunation of sheep

Michałowski

Harmeyer²,

Bełżecki³

1999

J. Anim. Feed Sci.

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Four different methods for defaunating were tested. Small Entodinia but some times also other species of ciliates were found on the next day after defaunation when Aerosol OT was given in doses of 5 and 10 g/animal or 1-1.5 g/kg of rumen content. Emptying and washing the reticulorumen with a 0.9% NaCl solution and subsequent freezing of the contents to -20°C for 96 h resulted in absence of protozoa for a period of 10-14 days and this was followed by the re-establishment of a population of Eudiplodinium maggii, Entodinium simplex and Dasytricha ruminantium. Emptying and washing of the reticulo-rumen with warm (40°C) water accompanied by heating of the contents to 70°C and addition of 10 g of Aerosol OT or 5 g sodium lauryl sulphate (SDS) eliminated the ciliates from the rumen for a period of 7-40 days but re-establishment of small protozoa like Entodinium simplex and Entodinium caudatum was observed later.Emptying the reticulo-rumen and washing the omasum, reticulum and rumen with warm water followed by heating of the contents to 70°C and the addition of Aerosol OT at a proportion of 1 g/kg digesta resulted in elimination of all the species of ciliates from the reticulo-rumen of all defaunated sheep for a period longer than 70 days.

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Section: Resultssupporting

confidence: 77%

Section: Resultscontrasting

confidence: 57%

The importance of washing the omasum for successful defaunation of sheep

Michałowski

Harmeyer²,

Bełżecki³

1999

J. Anim. Feed Sci.

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“…A possibly more efficacious defaunation technique involves total ruminal evacuation followed by washing of the rumen with water and then rinsing of the interior ruminal walls with dilute formaldehyde (11). However, after comparing various defaunation procedures, Lovelock et al (14) concluded that all of the techniques were ineffective in permanently removing ruminal ciliates. We also have been unable to achieve sustained defaunation in cattle using numerous putatively successful techniques.…”

Section: Discussionmentioning

confidence: 99%

Omasal ciliated protozoa in cattle, bison, and sheep

Towne

Nagaraja

1990

Appl Environ Microbiol

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Omasal contents were collected from slaughtered cattle (n = 54), bison (n = 15), and sheep (n = 40) to determine numbers and generic distribution of ciliated protozoa. Total protozoan numbers were significantly lower in omasal contents than in ruminal contents of all three species, but the percent composition of all protozoan genera was similar between omasal and ruminal populations. The highest numbers of omasal protozoa found were 7.61 x 105/g in cattle, 7.01 x 105/g in bison, and 1.29 x 106/g in sheep. Omasal dry matter was significantly higher than ruminal dry matter in all species and ranged up to 51.5% in cattle fed high-concentrate diets. The omasal pH was similar to the ruminal pH in all species. The number of omasal laminae averaged 149, 145, and 74 for cattle, bison, and sheep, respectively. Although protozoan concentrations in omasal contents were approximately 80% lower than those in ruminal contents, the omasum harbored relatively high numbers of ciliated protozoa. The resident omasal protozoa are extremely difficult to remove, particularly in cattle, and apparently are responsible for reinoculating transiently defaunated rumens.

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“…A meta-analysis has recently demonstrated that the benefits of defaunation outweigh any disadvantages (Eugène et al 2004). Antiprotozoal agents, such as surface-active agents, that have been investigated in attempts to apply defaunation at the farm level have been hampered by problems with toxicity, either to other rumen micro-organisms (Orpin, 1977;Bird & Leng, 1978;Bird et al 1979;Eadie & Shand, 1981) or to the host (Lovelock et al 1982). Lipids are toxic to protozoa (Newbold & Chamberlain, 1988;Matsumoto et al 1991;Machmuller et al 1998), and also to fibre digestion (Broudiscou et al 1994).…”

Section: Effects Of Saponins In Ruminantsmentioning

confidence: 99%

Antimicrobial properties of plant secondary metabolites

2004

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Increasing awareness of hazards associated with the use of antibiotic and chemical feed additives has accelerated investigations into plants and their extracts as feed additives. The present review mainly discusses two classes of plant secondary compounds in this context, i.e. essential oils and saponins. The broader potential of plants and their extracts is illustrated by the progress of an EC Framework 5 project, 'Rumen-up'. Dietary inclusion of a commercial blend of essential oils causes markedly decreased NH 3 production from amino acids in rumen fluid taken from sheep and cattle. This effect is mediated partly by the effects on hyper-NH 3 -producing bacteria and the protein-and starch-fermenting rumen bacterium, Ruminobacter amylophilus. Saponin-containing plants and their extracts suppress the bacteriolytic activity of rumen ciliate protozoa and thereby enhance total microbial protein flow from the rumen. The effects of some saponins are transient, because saponins are hydrolysed by bacteria to their corresponding sapogenin aglycones, which are much less toxic to protozoa. Saponins also have selective antibacterial effects that may prove useful in, for example, controlling starch digestion. The 'Rumen-up' project began with a targetted collection of European plants and their extracts, which partners have tested for their effects on rumen proteolysis, protozoa, methanogenesis and lactate production. A success rate of about 5 % in terms of positive hits illustrates that plant secondary compounds, of which essential oils and saponins comprise a small proportion, have great potential as 'natural' manipulators of rumen fermentation to benefit the farmer and the environment in the future.

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Difficulties in Defaunation of the Ovine Rumen

Cited by 20 publications

References 3 publications

The importance of washing the omasum for successful defaunation of sheep

The importance of washing the omasum for successful defaunation of sheep

Omasal ciliated protozoa in cattle, bison, and sheep

Antimicrobial properties of plant secondary metabolites

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